E21B 21/001 — IPC vs CPC Diff | Patent Classification Explorer

DIFF Subgroup

E21B 21/001

Full Title

Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (freeing objects stuck in boreholes by flushing E21B31/03)

This code exists only in CPC.

Diff view requires codes present in both systems.